Self-wiping electric plug connector



Dec. 25, 1945. H. KORN 2,391,425

I SELF-WIPING ELECTRIC PLUG CONNECTOR I I Filed Jan. 4, 1945 ,AZ reeY.kb/ew,

JAIVENTOE,

Patented Dec. 25, 1945 UNlTED STATES PATENT. OFFICE" 2,391,425SELF-WIPING ELECTRIC PLUG CONNECTOR Harry Korn, Los Angeies, Calif.

Application January 4, 1943, Serial No. 471,223

2 Claims.

This invention relates to a self-wiping electric plug connector.

An object of the invention is to provide an electric connector of theplug and socket type which is so designed that on insertion of the pluginto the socket the plug will automatically wipe and clean surfaces ofthe socket so as toform an excellent electrical connection between theplug and socket.

Another object of the invention is to provide an electric connector ofthe plug and sockettype wherein the plug may have its pin in the form ofa solid, smooth cylinder enabling the plug to be very sturdilyconstructed and to be readily cleaned with the resilient parts of theconnector disposed in the socket so as to be efiectively protectedthereby against damage.

Still a further object of the invention is to provide an electricconnector of the plug and socket type having a solid, rigid pluginsertable between resilient elements disposed in the socket and whichis so designed as to enable the parts to be very easily andinexpensively manufactured and readily assembled together,

With the foregoing and other objects in view, which will be mademanifest in the following detailed description and specifically pointedout in the appended claims, reference is had to the accompanying drawingfor an illustrative embodiment of the invention, wherein:

Figure I is a view in side elevation, parts being broken away and shownin section illustrating the plug element of the connector embodying thepresent invention;

. Fig. 2 is a longitudinal vertical section through the socket elementof the connector embodying the present invention;

Fig. 3 is a transverse section taken substantially upon the line 3-3upon Fig. 2;

Fig. 4 is a perspective view of the resilient elements in assembledrelation which form a part of the socket;

Fig. 5 is a view in side elevation illustrating the plug and socket ashaving been assembled together; and

Fig. 6 is a view in side elevation, parts .being broken away and shownin vertical section illustrating a slightly modified form of connectorembodying the present invention.

Referring to the accompanying drawing wherein similar referencecharacters designate similar parts throughout, the plug element of theconnector comprises a solidlength of metal providing a solid cylindricalpin In of suitable length. At the back of this pin the plug is enlargedas at II and preferably flatted as indicated at l2. It is equipped withan externallythreaded shank ii to which may be applied a sleeve l4formed of plastic, Bakelite, or the like which serves as a handle forthe plug.

The shank l3 has a hole I5 therein in which may be leaded the end of awire conductor, not shown, which extends through the sleeve l4 and whichis thus electrically connected to the plug. The socket illustrated inFig. 2 is in the form of a hollow cylinder [6 having at its forward enda flatted exterior l1 and which is externally threaded as at I8 for theapplication of a nut l9. The nut I9 is adapted to be tightened towardthe flatted large forward end of the socket in mounting the socket on aninstrument panel, The rear end of the socketmay be externally reducedand has a threaded aperture 20 therein adapted to receive a screw forthe attachment of a binding post to the back of the socket. The interiorof the socket has a cylindrical bore 2| formed therein ofadequate'length to receive the pin In of the plug. Adjacent the forwardend of this bore there is formed an annular groove 22 and the mouth ofthe bore is preferably countersunk or rounded as at 23 to facilitate thecentering and insertion of the plug into the socket and also tofacilitatethe insertion of the resilient elements of the socket. Theresilient, elements of the socket are preferably formed of aluminumphosphorus bronze- These are produced by bending a tape or ribbon ofthis material into a substantially U-shaped form. Each resilient elementthus has a bottom or back 24, forwardly extending arms or sides 25 and26 which terminate in outwardly extending flanges or lips 21 and 28.

In the construction illustrated there are two of such U-shaped resilientelements, these being exact duplicates of each other except that oneelement indicated at 29 is slightly shorter than the other, thedifference in length being merely equal to the thickness of the metal orribbon from which the U-shaped elements are formed. As originally orinitially constructed these U-shaped elements have their arms or sides25 and 26 slightly bowed in length as is illustrated in a somewhatexaggerated manner in Figs. 2 and 4. These U-shaped elements areconsecutively forced into the bore 2| and as they move into the bore theflanges or lips 21 and 28 engage the countersunk or rounded surface 23and cause the arms 25 and 2-6 to be sprung inwardly until the flanges orlips 21 and 28 are opposite the groove 22. The resiliency of the armsthen causes these flanges or lips to be sprung or snapped outwardly intothe groove 22 and the resilient element is thus retained in the socket.The U-shapcd resilient elements are preferably inserted in the socketconsecutively in this manner so that their arms occupy positions withinthe bore 2| as shown in Fig. 3. That is, the widths of the arms arearranged on chords across the interior circumference of the socket. Inthis manner the bore 2| of the socket is effectively lined with strips,namely the arms 25 and 26, of still, but nevertheless resilientmaterial. Inasmuch as the side edges of the arms engage the interior ofthe socket and the centers of the arms are in spaced relation to theinterior of the socket each arm may flex slightly across its width. Therectangle defined by the arms, as shown in Fig. 3, is slightly smallerthan the diameter of the pin it with the result that on forcing the pinI of the plug into the socket it engages the arms on longitudinallyextending center lines and flexes the arms outwardly slightly. As theplug is forced into the socket the leading edge of the pin eng es thearms and effectively wipes the arms throughout their lengths, pushingany dirt or corrosion that may accumulate on the arms to the back of thesocket and .thus wiping the arms clean so as to establish a goodelectrical contact between the arms and the socket. It will, of course,be appreciated that by reason of th fact that the arms are slightlyflexed they will maintain a firm frictional engagement with the pin illof the plug so as to retain the plug in the socket until it is forciblywithdrawn. When the plug is forcibly withdrawn the resilient elements ofcourse are retained in the socket by the flanges or lips 21 and 28 beingdisposed in the groove 2'2.

In the construction illustrated in Fig. 6, the connector is the same asthat above described except that th forward end of the socket isexternally threaded as at 3.0 adjacent a shoulder 3| on the fiattedexterior of the socket. A gasket 32 may be positioned against thisshoulder. A coupling or union 33 may be rotatably mounted on the plugand this is internally threaded for engagement with the threads 30whereby, upon the insertion of the plug into the socket, the union 33may be screwed on the socket against the gasket more or less permanentlyfasten the plug in the socket and provide a waterproof connection.

It will be appreciated from the above-described construction that theconnector can have its parts very easily and inexpensively manufactured.The plug and the body of the socket can both be turned out from stockmaterial on automatic screw machines with but very few operations. TheU- shaped resilient members can be shaped quite readily from ribbon ortape stock on a highspeed press or stamping machine. The assembly isreadily accomplished by merely forcing the U-shaped members into thesocket during which operation they will contract until the lips orflanges 21 and 28 are opposite the groove 22 and at that time theseretaining lips or flanges will be sprung into the groove to permanentlylock the resilient members in the socket. Inasmuch as the pin of theplug is solid, cylindrical, and smooth, it is quite sturdy. Heretoforeconnectors of this type have had the plug divided into a plurality ofresilient members which have been subject to the objection that they aredifficult to :lean and that they are easily damaged or sprung out ofshape so that they will not properly lit the socket. By having the pinof the plug cylindrical and smooth and also solid, it is very easy tothoroughly clean the plug and danger of the plug becoming sprung ordamaged is eliminated. Inasmuch as the resilient members of theconnector are housed within the socket they are effectively protectedthereby at all times. As each insertion of the plug will wipe thecenters of the arms 25 and 26 of the U-shaped resilient membersthroughout substantially their entire lengths, a clean, bright metalsurface is formed on each insertion for establishing an excellentelectrical connection between the resilient members of the socket andthe plug.

Various changes may be made in the details of construction withoutdeparting from the spirit or scope of the invention as defined by theappended claims.

I claim:

1. An electrical connector comprising a plug, a socket adapted toreceive the plug having a cylindrical bore therein, there being a groovein the wall of the bore adjacent the mouth of the socket and a pair ofU-shaped members disposed in the bore arranged in intersecting planeshaving laterally bent lips extending into the groove, the arms of theU-shaped members having their widths collectively lining substantiallythe entire interior of the socket with their edges in contact therewith,whereby upon insertion of the plug the arms will be caused to laterallyflex between their side edges to maintain firm engagement with the plug.

2. An electrical connector comprising a plug, a socket adapted toreceive the plug having a cylindrical bore therein, there being a groovein the walls of the bore adjacent the mouth of the socket and a pair ofU-shaped members disposed in the bore arranged in intersecting planeshaving laterally bent lips extending in the groove, the bottom of theU-shaped members being contiguously arranged and the arms of theU-shaped members having their widths collectively lining substantiallythe entire interior of the socket with their side edges in contacttherewith, whereby upon insertion of the plug the arms will be caused tolaterally flex between the side edges thereof. HARRY KORN.

